Canisters and other storage containers are in widespread use domestically and commercially, collectively referred to herein individually as a “canister” or “container” or as “canisters” or “containers” when there is more than one. It is typical for a canister to have a lid or cover that makes it re-sealable. For example, in food applications lids and covers can be used to keep foods fresh. In some applications it is desirable or necessary to have a canister with an airtight lid—particularly, but not exclusively, in food applications.
One example of a lid that can be used with a container is described in U.S. Patent Publication 2006/032852, entitled Airtight Lid For Container And Method Of Use, published Feb. 16, 2006. This publication describes a lid having a membrane made from a flexible material and having an outer perimeter larger than the rim of the container and a metal enforcement ring for establishing an airtight seal between the membrane and rim of the container. The lid may further comprise an air evacuation passageway having an air collection chamber for extracting air from the container and a valve for allowing air to flow out of the container, but preventing air from entering. The lid can be sealed to a container by pushing the membrane into the container and releasing the membrane to generate a vacuum. Without the enforcement ring the membrane would not form an airtight seal. One disadvantage to this type of lid is that it generally requires two hands to remove the lid, since the container must be steadied and held in place with one hand so the lid edge can be pulled up and away from the edge or rim of the container with the other hand.
Another example of a lid that can be used with a container is described in U.S. Patent Publication 2006/0151511, entitled Suction Cup Lid, published Jul. 13, 2006. This publication describes a lid made from a flexible material, e.g., silicone, forming a convex or other bulged shape. The lid includes a central handle or knob. When place on an opening of a container, the handle can be pressed downward causing the convex shape to be reduced or converted to a concave shape, while evacuating air from the container to form an airtight seal. The lid is made sufficiently wide so that an edge of the lid extends past the rim of the container. This allows the edge of the lid to be lifted up and away from the container to break the seal and remove the lid. Like the lid above, a disadvantage to this type of lid is that it generally requires two hands to remove the lid, since the container must be steadied and held in place with one hand so the lid edge can be pulled up and away from the edge or rim of the container with the other hand.
Another example of a lid that can be used with a container is described in U.S. Patent Publication 2006/0169693, entitled Silicone Lid For Sealing Any Type Of Open-Ended Container, published Aug. 3, 2006. This publication describes a lid that can be sealed to a container by placing a bottom of the lid on an open-ended side of the container and depressing the top, forcing air out of the container and forming a vacuum seal. The lid is substantially flat and wider than the opening it is sealing. To remove the lid a protrusion that extends outwardly from an edge of the lid is pulled up and toward the center of the lid to break the vacuum seal—i.e., to open the container. Similar to the lids described above, a disadvantage to this type of lid is that it generally requires two hands to remove the lid, since the container must be steadied and held in place with one hand so the lid can be pulled up and away from the edge or rim of the container with the other hand.